Sex-specific regulation of gene expression in the aging monkey aorta

Although increased vascular stiffness is more prominent in aging males than females, and males are more prone to vascular disease with aging, no study has investigated the genes potentially responsible for sex differences in vascular aging. We tested the hypothesis that the transcriptional adaptation to aging differs in males and females using a monkey model, which is not only physiologically and phylogenetically closer to humans than the more commonly studied rodent models but also is not afflicted with the most common forms of vascular disease that accompany the aging process in humans, e.g., atherosclerosis, hypertension, and diabetes. The transcriptional profile of the aorta was compared by high-density microarrays between young and old males or females ( n = 6/group). About 600 genes were expressed differentially when comparing old versus young animals. Surprisingly, <5% of these genes were shared between males and females. Radical differences between sexes were especially apparent for genes regulating the extracellular matrix, which relates to stiffness. Aging males were also more prone than females to genes switching smooth muscle cells from the “contractile” to “secretory” phenotype. Other sex differences involved genes participating in DNA repair, stress response, and cell signaling. Therefore, major differences of gene regulation exist between males and females in vascular aging, which may underlie the physiological differences characterizing aging arteries in males and females. Furthermore, the analyses in young monkeys demonstrated differences in genes regulating vascular structure, implying that the sex differences in vascular stiffness that develop with aging are programmed at an early age.

Aging increases aortic MMP-2 activity and angiotensin II in nonhuman primates

To seek evidence that the nonhuman primate arterial wall, as it ages in the absence of atherosclerosis, exhibits alterations in pathways that are involved in the pathogenesis of experimental atherosclerosis, we assessed aortic matrix metalloproteinase-2 (MMP-2) and its regulators, ie, membrane type-1 of matrix metalloproteinase (MT1-MMP) and tissue inhibitor of matrix metalloproteinase-2 (TIMP-2), and the expression of angiotensin II (Ang II), angiotensin-converting enzyme (ACE), and chymase in young (6.4+/-0.7 years) and old (20.0+/-1.9 years) male monkeys. With advancing age, (1) the intimal thickness increased 3-fold and contained numerous vascular smooth muscle cells and matrix, but no inflammatory cells; (2) the intimal MMP-2 antibody-staining fraction increased by 80% (P<0.01); (3) in situ zymography showed that MMP-2 activity, mainly confined to the intima, increased 3-fold (P<0.01); (4) the MT1-MMP antibody-staining fraction increased by 150% (P<0.001), but the TIMP-2 antibody-staining fraction did not significantly change; (5) steady levels of the mRNA-staining fraction (via in situ hybridization) for MMP-2 increased 7-fold, for MT1-MMP increased 9-fold, and for TIMP-2 increased 2-fold (all P<0.001); and (6) intimal Ang II and ACE immunofluorescence were increased 5-fold and 5.6-fold, respectively, and colocalized with MMP-2. Thus, age-associated arterial remodeling and the development and progression of experimental atherosclerosis in young animals share common mechanisms, ie, MMP-2 activation and increased Ang II signaling. This might explain, in part, the dramatically exaggerated prevalence and severity of vascular diseases with aging.

Conditioning and breeding facilities for the cynomolgus monkey (Macaca fascicularis) in the Philippines: a progress report on the SICONBREC project

Large-scale breeding of Macaca fascicularis in the country of origin is a way in which the demands of the research community can be met whilst the feral population of monkeys is safeguarded. The establishment of the SICONBREC project and the success of its breeding programme to date is clear evidence of the future trend in the supply of non-human primates for biomedical research.